Lower unit for concrete finisher



-Nov. 3, 1959 J. w. THIEME ET AL 2,910,923l

LOWER UNIT FOR CONCRETE FINISHER Filed Feb. 3, 1956 2 Sheets-Sheet l #rra/ways.

Nov. 3, 1959 l .1. w. THIEME ETAL 2,910,923

LOWER UNIT FOR CONCRETE FINISHER Filed Feb. s. 195e z sheets-sheet 2 United States ,123mm LOWER UNIT FOR CONCRETE FINISHER lohn W. Thieme, West Compton, and Patrick J. McDonnell, Compton, Calif.; said McDonnell assignor to said Thieme The invention relates to rotary concrete finishing machines of a type wherein a motor mounted upon the housing causes a hub to rotate which in turn mounts a plurality of horizontal radially extending blades which during rotationwork, finish or surface moist concrete. -In this type of device the blades themselvescarry the weight of the apparatus. 1

In the last decade there has been an increasingamount of attention given to machines whereby use of power is employed to expedite the working of concrete. and especially the finishing operations. It has been foundthat even by the use of relatively small power units where such units are employed to decrease the physical effort of an operator and increase his comfort while working, a. tremendous increase in productivity invariably follows. This thought has prompted the building and operation of rotary concrete inishing machines of the general type suggested. As in the early development of most new things, those machines heretofore devised for this purpose havebeen somewhat clumsy and awkward and have employed to a large extent a rather large number of separate parts in an attempt to supply features of adjustment which appear to be needed. Among necessary adjustments is that of the tilt of the blade. In some machines heretofore produced it has been necessary to set the tilt of the bladein advance of operation and then to stop the machine `ifthe blade tilt'is to be reset; Other machines have provided manually actuated mechanisms for tilting the blade during operation. In rare instances as, for example, in co-pending application Serial No. 518,088, filed June 27, 1955, power generated for the purpose of rotating the blades has beenV taken advantage of in an auxiliary power train to effect adjustment of the blades `during operation subjectfto manualcontrol at the handle. Employment of hydraulicV power` has become an effective medium for such adjustments'as pointed out in the co-pending application.

Among the objects of the invention here presented is to provide a new and improved rotary concrete` finishing machine wherein tiltable rotating blades are adapted to be adjusted by the employment of hydraulic power through a simple, direct-acting mechanisml which more effectively makes use of hydraulic power generated. by the main power source for adjustment of the blades.

Another object of the invention is to provide a new and improved adjustable blade mounting which has moving parts thereof effectivelysealed against ingress of moisture and wherein considerable latitude of blade adjustment is achieved without the necessity of providing for any great latitude of movement in the application of power.

Still another object of the invention is to provide a new and improved lower unit for a rotary concrete finishing machine wherein shafts for the blades may be permanently mounted in a rotary housing but wherein the shaftsvare so constructed that blade elements of different types and sizes can be mounted upon the bladeshaftsto suit individual or special conditions without it being necessary to make any change whatsoever in the blade shaft or the manner 'in which it is mounted upon the machine.

A stillfurther object of the invention .is to provide a newand improved tiltable blade assembly for a rotary concrete finishing machine wherein permanently mounted and pivoting biade shafts have attached thereon blade elements secured to the shaft in such fashion that no matter to what tilted position the blades may be set, a substantial proportion of each blade remains in smooth working relationship with the surface of the concrete being worked to assure a rapid, even and dependable finish regardless of the angle of tilt of the blade.

Also included among the objects of the invention is to provide a new and improvedblade for attachment to the blade shaft of a rotary concrete finishing machine which islight in weight and versatile of performance and which at` the same time is specially reinforced overportions thercofextending beyond a point of engagement with the shaft, thereby to assure uniformity in the application of pressure by the blade throughout the entire length and breadth of the blade regardless of the length of blade employed.

With these and other objects in View, theV invention consists in the construction, arrangement and combination of thel various parts of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated: in the accompanying drawings.

In tl'iedrawings:`

Figure` l is a fragmentary longitudinal. sectional Viewy of the lower portion of a rotary concreteV finishing machine showing the blademounting andadjusting mechanism.

Figure 2 is a fragmentary cross-sectional View taken on the line 2--2 of Figure l.

Figure 3 is a cross-sectional view of a blade and blade. shaft taken on the line 3--3 of Figure 2 with the blade in. neutral position of adjustment such` as it would have at rest.

Figure 4 is a cross-sectional view similar to Figure 3 showing the blade adjusted to. a selected degree of tilt.

Figure 5 is a fragmentary longitudinal sectional View similar to Figure l wherein the blade attached to the blade shaft is one shorter in length than theblade shaft of Figure l.

In an embodiment of the invention chosen for, the purpose of illustration there is shown a portion of a housing iti of a concrete finishing machinein which is a bearing block li. A rotor shaft 12 is rotatablyl mounted in bearing rings i3 and 14 in the bearingblock. One of the gears 15 employed to drive the rotor shaft is shown located in a chamber 16.

Within the rotor shaft is a hydraulic chamber 17 into whichihydraulic fiuid under pressure may be introduced through a passage 18. At the lower end of the rotor shaft l2 is a casing i9 non-rotatablyl secured to the shaft by a suitableconventional attachment. The-casing 19'comprsea a body Ztl anda top member 21 to which the body is secured by means of suitable machine screws 22. A series of bearing blocks 23, four in number in the. present instance, extend horizontally and4 radially outwardly from a vertical cylindrical wall 24 of the body 2t). ln each of the bearing blocks 23 there is mounted a shank 25 ofia blade shaft 26. A shoulder 27 and application of a ring 28 secures each of. the Shanks. in its fixed rotatable position in the bearing block. An innerend 29 of the shank 25 extends into achamber 31Min the casing 19. At the innermost end of each shankv is a collar 31 non-rotatably secured to the shank, upon which is fixed a cam or cam arm 32. A snaplring 33 may be employed to hold the collar on the inner end of ythe shank and some suitable key 34 employed in order to non-rotatably mount one upon the other. A cam plate 35 lies in a horizontal direction extendmg over the top of each of the cam arms 32. The cam plate is non-rotatably attached to a piston rod 36 by means of a set screw 37. The piston rod in turn has a piston 38 mounted thereon and adapted to be slidably received within the hydraulic chamber 17. A packing gland 39 slidably mounts the piston rod 36 for smooth reciprocating operation. The packing gland also closes the lower end of the hydraulic chamber 17.

The blade shaft 26 in each instance may be provided with vertically extending holes 45 and 46, the hole 4S being located adjacent an outer end and the hole 46 being located more nearly the inner end of the blade shaft. It will be noted that the blade shafts are permanently positioned in the Kbearing bosses of the casing 19 and in that position when the holes 45 and 46 are in vertical position, the cam plate 35 is retracted and the cam arms 32 are tilted to their uppermost positions which is oblique with respect to vertical as indicated in Figure l.

As illustrated in Figure 1 a relatively long blade member 47 is shown secured to the blade shaft 26 by means of angle brackets 48 and 49. Each angle bracket comprises a vertical arm 50 and a horizontal arm 51. The vertical arm is of reduced diameter providing thereby a shoulder 52 and extends upwardly through the respective hole wherein it is firmly secured by means of a nut 53 and lock washer 54.

A troweling blade 55 has a trailing edge 56 and a leading edge 57. The leading edge is upturned in the direction of its approach over a surface 58 of a mass 59 of moist concrete. Immediately at the rear of the leading edge 57 is a rib 60. The rib extends throughout substantially the length of the troweling blade and consists of a horizontal flange 61 and a vertical flange 62. The horizontal flange has the troweling blade firmly secured to it by some conventional means such, for example, as ush riveting or welding. The horizontal arm 51 of each of the brackets extends through the vertical flange at an appropriate location and is fastened in place by means of a nut 63 and lock washer 64.

It should be noted particularly that the portion of the vertical flange 64 lying between the angle brackets 48 and 49 has a uniform height. troweling blade 55 is a section 66 of the vertical flange which is of progressively increasing height from the point of attachment to the bracket 48 to the outermost end. Similarly a section 66 of the horizontal frange 61 is of progressively increasing thickness. These sections by reason of their greater respective height and thickness provide a greater rigidity for the unsupported outermost end of the troweling blade 55 so that there is a uniformity of rigidity in the troweling blade throughout its entire length. By this construction when blades are employed which extend to any appreciable degree beyond the outermost end of the blade shaft 46, regardless of the length of the chosen blade, suicient rigidity will be assured so that there will be a uniform application of force between the blade and the surface S8 throughout all of the length and breadth of the blade.

Another important element to considered is the mounting of the rilb at the leading edge of the troweling blade and the securement of the blade by brackets, horizontal arms of which have considerable length extending rearwardly to approximately the central axis of the troweling blade.

As has already been indicated, the blade members normally support the weight of the entire machine upon the surface 58 which is to be finished. This is the position shown in Figure 3 and in that position the troweling blade by reason of its inherent resiliency lies at on the surface. pressure is conveyed through the passage 18 into the hydraulic chamber 17, the effect of which is to move the piston 38 downwardly an amount determined by the amount of hydraulic uid which is admitted to the cylinder. As the piston moves downwardly, the piston rod 36 transfers the motion to the cam plate 35 which in turn presses upon each of the cam arms 32 to an equal degree, causing them to rotate in a counter-clockwise direction as viewed in Figure l. of each of the blade shafts 26 counter-clockwise as viewed also in Figure 4. As the blade shaft is rotated,

Y the leading edge 57 of the troweling blade 55 is elegreater pressure will be needed to be sure that portionsV vated to a position somewhat like that shown in Figure 4. Because of the center of gravity 'being applied at approximately the longitudinal axis of the troweling blade, only the forward portion, approximately the forward half, of the troweling blade will be lifted While the trailing half remains in contact with the surface 58 throughout a very considerable portion of its area. The inherent resilience in the troweling blade will result in there being a very acute angle 65 existing between the lower surface of the troweling blade and the surface of the cement to be finished. The degree of angle increases toward the leading edge of the troweling blade. Regardless of the extent of tilting of the blade, there will always remain a reasonably acute angle 65 although the location of the angle will progress toward the trailing edge of the blade as the degree of tilt is increased. The effect of an increase in tilt, however, is to produce a greater degree of Working pressure upon the moist mass 59 of concrete. In the early stages of finishing a of the'rough aggregate are pressed a sufficient distance below the surface 58. For the final surfacing of the concrete only a very slight degree of tilt will be necessary, in which event a relatively large proportion of the v surface area of the troweling blade will be in contact At the outer end of the with the surface 58. This is the final finishing operation of the concrete.

On those occasions where it may be advisable to use blades of lesser length a blade member 67 such as that shown in Figure 5 may be employed. ln this instance the blade member comprises a troweling blade 68 on the upper surface of which is mounted a rib 69. In this instance a vertical flange 70 of the rib is uniform in height throughout its length and a horizontal ange 71 is uniform in thickness throughout its length. The blade member is of such length that it terminates approximately Hush with the outermost end of the same blade shaft 2-6 as is employed in connection with the longer blade member described in connection with Figures l through 4,

'- inclusive. The same angle brackets 48 and 49 may be employed, mounted in the same fashion both with respect to the ange 743 and the blade shaft 26. In all other respects the mechanism is the same as that already described in connection with Figures 1 through 4, inclusive.

There has accordingly been described herein what may be termed as a lower unit for a rotary concrete finishing machine wherein a simplified adjusting mechanism is provided for adjustment of the tilt of the blades by use of hydraulic power and wherein the blades subject to adjustment are mounted in a particular fashion which assures a smooth traveling effect using a substantial portion of the area of the blade in each instance in all posi-` tions of adjustment.

While we have herein shown and described our invention in what we have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of our invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the Claims so as to embrace any and all equivalent devices.

When the blade is to be tilted, hydraulicl The result is rotation Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A rotary concrete finishing machine comprising a lower member and an upper member, said lower member comprising a rotatable lluid tight casing substantially at floor level having a completely enclosed cam chamber therein and a plurality of radially extending elongated bearing blocks, a cover assembly forming a top for said casing and including a shaft fixed thereto and having a hydraulic cylinder therein at the axis of rotation of the casing, a piston reciprocatably mounted in the cylinder, a piston rod on the piston extending downwardly into the chamber, a bearing guide for the piston rod at the top of the chamber, and a cam plate in the chamber at the lower end of the piston rod rotatable with said casing, said piston and said piston rod, a blade shaft in each bearing block having at its inner end a single rotatable mounting in the bearing block and having a free outer end, a troweling blade for each shaft, and bracket means securing said troweling blade to the shaft, said inner end of the blade shaft having a portion thereof within the chamber, a cam on said inner end in engagement with the cam plate within said chamber, said upper member comprising a housing, said shaft being rotatably journalled in the housing at a location above said hydraulic cylinder and comprising the sole connection between said upper and lower members, the upper portion of said shaft being provided with a passageway communicating with said cylinder to conduct hydraulic tluid from said upper member through said shaft to said hydraulic cylinder whereby to adjust said blades by means confined entirely inside said upper and lower members.

2. A rotary concrete tinishing machine comprising a rotatable fluid-tight casing substantially at oor level having cam actuating means therein, said casing having a plurality of radially extending elongated bearing blocks, a rod reciprocatably mounted in the casing, a bearing guide for the rod at the top of the casing and a cam plate at the lower end of the rod, a blade shaft for each bearing block having at an inner end a single rotatable mounting in the bearing block and having a free outer end, each said blade shaft being located with its axis of rotation intersecting the axis of rotation of the casing, a troweling blade on each shaft, and a plurality of bracket means securing each troweling blade to its respective shaft, said inner end of each blade shaft having a portion adjacent said cam plate, a cam on said inner end in engagement with the cam plate, a housing having a center line in axial alignment with the axis of rotation of the casing, said housing having a rotatable connection with the casing at the axis of rotation thereof, reciprocating means for said rod, said bracket means comprising arms on the blade shaft extending a substantial distance forwardly relative to the axis of rotation of the blade shaft, a stiifener attachment rib secured to the leading edge of each blade, each rib being secured to the forward ends of said arms and extending along and parallel to said leading edge, each said blade being otherwise unsupported except at the stiffener rib and being spaced below its respective blade shaft, a substantial portion of each blade extending rearwardly of its shaft whereby rotation of the shafts cause the blades to liex in a place transverse to the shafts.

References Cited in the tile of this patent UNITED STATES PATENTS 2,181,375 Leistner Nov. 28, 1939 2,198,929 Whiteman Apr. 30, 1940 2,277,389 Conway Mar. 24, 1942 2,394,274 Troxell Feb. 5, 1946 2,468,981 Huffman May 3, 1949 2,662,454 Whiteman Dec. 15, 1953 2,689,507 McCrery Sept. 21, 1954 

